语言理解过程中,句子内部的韵律短语边界会诱发反映韵律短语终止的特异性脑电成分终止正漂移(CPS,closure positive shift),而句末语调短语边界则会诱发反映句法终止和完整语言单元结束的脑电效应P3。研究采用汉语特有的语篇绝句,考察了听者加工绝句中各句末语调短语边界的认知过程及其诱发的脑电效应。结果发现五言绝句内部各语调短语边界分别诱发了时间进程、头皮分布和波幅均相同的CPS,表明语篇内部韵律边界加工不受其所处语篇位置的影响;五言和七言绝句末的韵律边界则分别诱发了一个P3,并且前者诱发的P3波幅小于后者,而二者在时间进程和头皮分布上不存在差异。本研究表明,句末语调短语边界诱发何种脑电效应与其承担的功能有关,既表示前面信息终止又预期后面信息出现的句末边界会诱发CPS,而只表示信息终止的句末边界则会诱发P3。
Prosodic boundary, as an integral part of prosodic features in spoken language, is very important in sentence and discourse comprehension. Recently, researchers have shown increasing interest in the neural mechanism of prosodic boundary processing. Numerous studies have found that CPS, a special ERP component reflecting the closure of phonological phrase, could be induced by phonological phrase boundary embedded in a sentence. Also, researches have demonstrated that intonational phrase boundary in the end of a sentence consistently elicited P3, which reflects the operation of "syntactic closure" as well as the completeness of language unit. The present study aims to investigate the cognitive processing of intonational phrase boundary embedded in discourse and its related brain effect using ERP. To explore the processing of intonational phrase boundary in discourse, quatrain was used, which is composed of four sentences and five or seven characters in each sentence. Twenty (10 males) healthy undergraduates participated in the experiment. The participants were told to listen carefully to each poem, and complete a word discrimination task. Specifically, if the word "Space" was presented, they were asked to press the spacebar to continue. If other words were presented, they were required to press the "F" or "J" key to indicate whether the word appeared in the poem they had just heard. The EEG was recorded from 64 scalp channels using electrodes mounted in an elastic cap. Boundary-related ERPs were calculated for a 1500 ms epoch including a 200 ms pre-boundary syllable baseline. It was found that the three intonational phrase boundaries embedded in the quatrain elicited CPS respectively, with no differences in time course, amplitude and scalp distribution, indicating that prosodic boundary processing was not influenced by its position in discourse. Moreover, the final sentence of both five-character-quatrain and seven-character-quatrain evoked the P3 effect, with the amplitude elicited by the forme